Epidemiological and molecular characterization of a Trichophyton tonsurans epidemic in schools of a city in the northern suburbs of Paris, France

Abstract

received a report regarding a possible epidemic of dermatophytosis in a school group from Clichysous-Bois (in the northern suburbs of Paris). All the children of this school group were screened for dermatophytosis by clinical and mycological examinations. During the 15 months following this first report, children from eight other schools in this city, and members of their families, came to the same ParasitologyeMycology department for dermatophytosis screening. The main goal of this investigation was to identify the causative agents and then to evaluate the intraand inter-specific genotypic relationships of the isolated dermatophytes. For this purpose, suspected lesions of hair or skin were sampled by scraping and swabbing and demographic data (age, gender, geographical origin, familial links and source of contact) were recorded in parallel as part of the routine procedure for mycological diagnosis. Direct microscopic examination of hair and scales was performed in sodium sulphide with 0.1% Blankophor by fluorescence microscopy. After this, the samples were inoculated on Sabouraudechloramphenicolegentamicin medium agar slants with or without cycloheximide adjunction (Bio-Rad, Marnes-la-Coquette, France) and kept at 25 C for at least 3 weeks. Once a week, the cultures were examined macroscopically and microscopically to identify the dermatophytes at species level. A dermatophytosis case was determined by positive direct microscopic examination (presence of fungal filaments or spores in hair or scales) and/or positive dermatophyte culture.Next, to evaluate the intra-and inter-specific genotypic relationships among the Trichophyton tonsurans isolates, which were in the majority in this epidemic, they were subjected to conventional PCR and sequencing of two fragments of the alkalin protease 1 (ALP1) gene [1]. For this purpose, we selected two regions of interest on this gene for their high degree of polymorphism and amplified them using the pairs of primers ALP1-1/10 and ALP1-9/2 [1]. Our obtained sequences were aligned using BLAST (the Basic Local Alignment Search Tool) and compared with the sequences deposited in GenBank.In total, 122 individuals (116 school children, four infants and two adults) were evaluated by clinical and mycological examination for probable dermatophytosis in nine school groups located in Clichy-sous-Bois, leading to 139 samples for mycological examination. Eighty-one individuals (92 samples) were diagnosed positive for dermatophytosis (66.4%), including 31 individuals (31 samples) positive for direct microscopic examination only, and 53 individuals (61 samples) positive for dermatophyte culture. The positive individuals presented tinea capitis (84.8%) or tinea corporis (15.2%). Among positive cultures (61 cases), a large majority (52 isolates, i.e. 85.2%) were positive for T. tonsurans, followed by 6.6% Trichophyton rubrum, 5% Microsporum audouinii, 1.6% Trichophyton soudanense and 1.6% Microsporum canis.The infected individuals ranged in age from 3 months to 53 years with an average of 8 ye...

Effect of Household Laundering, Heat Drying, and Freezing on the Survival of Dermatophyte Conidia

“…In children, tinea capitis (TC) is the most frequent fungal infection and a widespread health problem all over the world. Over the past decade, TC of anthropophilic origin has significantly increased, particularly in urban areas, leading to epidemics in children’s communities [ 2 , 3 , 4 ].…”

Atypical extensive tinea corporis caused by Trichophyton tonsurans

“…Trichophyton tonsurans is associated with both tinea capitis, the most common superficial mycosis in school-age-children, and tinea corporis (Vingataramin et al, 2019). The clinical manifestations are variable from asymptomatic carriers to patients with inflammatory manifestations (Shimoyama et al, 2016).…”